Synthesis of Ti3SiC2 from powder blend of Ti, Si and TiC

Titanium silicon carbide Ti3SiC2 was synthesized from a powder blend of Ti, Si and TiC at a molar ratio of Ti:Si:TiC = 2:2:3. The powder blend was pressed and shaped into a cylinder and then sintered at various temperatures in vacuum. X-ray diffraction analysis was conducted on the cylinders sintered at various temperatures. Results of the XRD analysis revealed that Ti5Si3, the most thermodynamically stable phase in Ti–Si system, was preferentially formed by the reaction between Ti and Si powders followed by the formation of TiSi2 from remaining Ti and Si powders in a relatively low temperature range. These silicides reacted with TiC to form Ti3SiC2 at higher temperatures. The final phases in the cylinders sintered at temperatures over 1729 K were Ti3SiC2 and Ti5Si3, which well agrees with those estimated by a Ti–Si–C phase diagram. On the other hand, final phases in disks sintered under pressures of 14 MPa or more by using a carbon mold were found to be Ti3SiC2 and TiC, which suggests the equilibrium changes with the pressure.